This invention relates specifically to the safe storage of pen needle assemblies (sometimes referred to herein as PNAs). Because of well known health issues, the safe disposal of medical/other syringes has long been a high priority for the related professions and industries. The prior art containers for such syringes are commonly termed “sharps containers” and many configuration of these are found in public venues such as hospitals, medical clinics, and retail establishments. These containers are usually securely attached to some base means and have a lock means to permit controlled and safe removal of used “sharps.”
Medical delivery pens have, more recently, become widely used, e.g., by diabetics, who frequently inject themselves several times a day with accurately measured amounts of insulin or other medication. Medical delivery pens include a reservoir of medication and a distal end adapted to be attached (usually by thread means) to a pen needle assembly. As is well known, the pen needle assembly has (within an outer, generally cylindrical shield) a generally cylindrical housing within which is mounted an axially extending hollow needle, (i) the proximal end of which punctures a seal in the distal end of the medical delivery pen (to allow the flow there-through of medication) when the delivery pen is screwed into the proximal end of the pen needle housing, and (ii) the distal end of which is for insertion into tissue of the person requiring the medication. The pen needle assemblies typically include a removable seal covering the proximal (large diameter) end of the said outer shield and a removable tube-like shield covering the distal portion of the hollow needle. The assembled pen needle assembly is then factory sterilized. The user of a pen needle assembly removes the seal from the outer shield, screws the pen into the proximal end of the pen needle housing, removes the outer and tube-like shields, sets the medical delivery pen for the desired dose of medication, and then inserts the distal end of the pen needle into the target tissue following which the medical delivery pen is actuated to deliver the desired dose of medication through the hollow needle into said tissue.
In a perfect world, the user of a pen needle assembly would, after the first use of a pen needle assembly, carefully detach the used pen needle assembly from the medical delivery pen and safely dispose said assembly. The approved procedure is (i) insertion of the distal end of the needle into the tube-like shield and thence the shielded needle and cylindrical housing into the outer shield, (ii) unscrewing of the medical delivery pen from the proximal end of the pen needle housing, and (iii) placement of the used pen needle assembly into a safe sharps container. Alas, the recommended procedure is not always followed. Used (and potentially dangerous) pen needles, with or without outer shields, are routinely left in unsafe places where third parties may unwittingly be “stuck.” Examples of such unsafe places are purses, the seat pockets on the back of aircraft seats, private and public wastebaskets, garbage cans, dumpsters and empty milk bottles or other unsafe containers.
One prior art example of a container for used pen needle assemblies is U.S. Pat. No. 5,545,145 which shows a tube containing a small number of unused pen needle assemblies arranged in axial alignment. This patent also teaches that, as unused assemblies are removed from one end of the tube, then a used assembly may be inserted into the tube from the other end. The tube is adapted to be attached to the side of a medical delivery pen. This arrangement has certain shortcomings. The capacity is quite limited and, potentially dangerous “sticks” could occur when a user tries to insert a used assembly (without the protective outer shield) into the used end of the tube.
Other prior art sharps containers may be used for disposal of used pen needle assemblies; however they are typically far too large and bulky and have other disadvantages.